Exploring Neuromelanin's Significance: Comparative Insights from Advanced MRI Techniques for Diagnosing Early-Stage Parkinson's Disease

Motivation: Early diagnosis of Parkinson's disease (PD) is challenging due to overlapping clinical features. While various imaging methods have been developed, direct comparative studies remain underexplored. Goal(s): To evaluate and compare the diagnostic performance of free water (FW), neuromelanin (NM), and diffusion tensor imaging (DTI) in identifying early-stage PD. Approach: FW and NM values in the substantia nigra (SN) and DTI metrics in white matter tracts were assessed. Results: Early PD patients showed reduced NM in SN, with no FW differences, and decreased integrity in the corona radiata and corpus callosum. NM in SN demonstrated the highest diagnostic accuracy. Impact: Our study highlights NM imaging in the SN as a superior biomarker for early Parkinson's disease diagnosis compared to other imaging methods, offering clinicians a more reliable diagnostic tool.